Continuation of work directed toward the total synthesis of the macrolide antibiotics boromycin and verrucarin A is planned. Coupling studies, utilizing synthetic segments corresponding to four quadrants of boromycin, will be pursued in an effort to prepare the complete northern and southern halves of the macrolide. Natural boromycin will be degraded to substances which are intended to provide relay compounds, and further studies on the reconstitution of boromycin from these segments will be undertaken. Attempts to prepare the macrolide units of verrucarin A and the roridins will be continued along lines recently developed in a successful approach to the corresponding unit of verrucarin J. Coupling of these dicarboxylic acid moieties with natural verrucarol will be investigated. An approach to the total synthesis of verrucarol, in which construction of the bridged BC ring system is to take place via a cyclobutenylcarbinol-to-cyclopentenol rearrangement, will also be studied.